Spectral images of the Io plasma torus from about 165 hours
of observation by the Extreme Ultraviolet Explorer (EUVE)
spacecraft were analyzed by a spectral-resolution-enhancing
deconvolution algorithm in order to estimate averaged torus
properties during Galileo's I24 torus encounter and also in
June, 1996. Because of our analysis' improved spectral
resolution (\Delta\lambda\approx1 to 2\thinspaceÅ), we
are able to separate lines arising from different ion
species better than in earlier studies. Here we estimate
emission-weighted whole-torus averages of electron
temperature and ion fraction.

Comparing the 1996 and I24 observations, the torus electrons
were hotter (5.5±.5 vs 4.6±.3\thinspace eV), the
torus was brighter (2.9 vs 1.9\times1011\thinspace W
over 350\leq\lambda\leq735\thinspaceÅ), and the
sulfur/oxygen ratio was higher (0.8 vs 0.55) in the earlier
epoch. When separately analyzing the dawn and dusk halves of
the torus during I24, we estimate that the dusk half is a
few tenths of an eV hotter than at dawn. In our
presentation, we will discuss analysis of the data by System
III longitude and orbital phase relative to Io.

We have also put new constraints on the values of electron
impact collision line strengths for many EUV lines in the
range 350\leq\lambda\leq735\thinspaceÅ\ that are of
interest for understanding the torus and other sulfur and
oxygen plasmas. These numbers are useful for modeling EUV
torus spectra at both moderate and low spectral resolution.

This work was supported by the NASA Planetary Atmospheres,
Planetary Magnetospheres, and JSDAP programs.